The scale of the hunt for missing flight MH370 took on new geo-political dimensions yesterday after the Malaysian authorities revealed the search area has now been extended to 6.2 million square kilometres.

As the mystery over the Malaysia Airlines Boeing 777 jet with 239 passengers and crew on board enters day 12, Malaysian officials issued a new plea for countries to provide information.

We are asking partners … to take another look at primary radar data

HISHAMMUDDIN HUSSEIN, MINISTER

Their call - for what in some cases is sensitive military data - illustrates how the search for MH370 has become not only a massive logistical operation covering vast expanses of land and ocean, but a political and diplomatic quagmire.

Malaysia is the only country so far to have shared sensitive military data with other nations to narrow the search by "putting passengers and the plane above national security", it says.

The sheer size of the task facing investigators came as Beijing's ambassador to Malaysia, Huang Huikang, said China had ruled out the possibility of terrorist activity by any of the 154 Chinese on the plane.

Huang said China had "conducted meticulous investigations into all the [Chinese] passengers, and did not find any evidence of sabotage activity".

Thailand's military revealed last night its radar detected a plane that may have been MH370 minutes after the plane's communications went down.

It said it did not share the information earlier because it wasn't specifically asked for it.

Thai air force spokesman Montol Suchookorn said the plane followed a twisting flight path to the Strait of Malacca, which is where Malaysian radar tracked it to early on March 8.

He said the plane did not enter Thai airspace.

Over the last two days, Malaysia has been in talks with nations in the northern and southern corridors of the search - from Kazakhstan in the north to the southern Indian Ocean - for information and support.

About 20 aircraft and ships have been deployed in the Indian Ocean as part of a hunt covering 26 nations. Flight MH370 took off for Beijing from Kuala Lumpur on March 8 before vanishing.

Hishammuddin confirmed appeals for data had been made to "relevant" countries and added: "We are asking international partners … to take another look at their primary radar data."